Potatoes and apples that have been genetically engineered to resist discoloration from bruising have been approved by the U.S. Food and Drug Administration (FDA).

The agency said on Friday that it had completed its evaluation for two varieties of apples genetically engineered by Okanagan Specialty Fruits, Inc., and for six varieties of potatoes genetically engineered by J. R. Simplot Company.

Okanagan's Granny Smith and Golden Delicious apples, known collectively by the trade name "Arctic Apples," are said to resist browning associated with cuts and bruises by reducing levels of enzymes that can cause browning. The company believes this will extend their shelf life and enhance consumer appeal.

In a similar fashion, Simplot has genetically engineered three varieties of potatoes to reduce the formation of black spot bruises by reducing levels of certain enzymes. The potatoes are also engineered to produce less asparagine and reducing-sugars, thereby lowering the potential for acrylamide formation during high-temperature cooking, such as frying.

Simplot's varieties of Ranger Russet, Russet Burbank and Atlantic potatoes are collectively known by the trade name 'Innate'.

After assessing safety and other data on the new varieties, the FDA concluded that the foods are as safe and nutritious as their conventional counterparts.

Whether food producers will welcome the new varieties remains to be seen, however. The Associated Press reported on Friday that ConAgra and McDonald's had both said they have no plans to use potatoes made from genetically modified organisms (GMOs).

"McDonald's USA does not source GMO potatoes nor do we have current plans to change our sourcing practice," the restaurant group said in a statement.